This protocol defines in general terms the purposes for which blood, urine and ultrafiltrate will be collected from adult research subjects and healthy volunteers by members of the NIH Clinical Center's Critical Care Medicine Department and collaborating institutions and establishes general conditions under which sampling will be performed. Blood drawing will be consistent with NIH Clinical Center guidelines. The Critical Care Medicine Department and our associated investigators are involved in the development of new translational research protocols and maintenance of existing IRB approved research protocols. This protocol will support the establishment of new translational research protocols through assay development and provide information to guide the effective implementation of new protocols as well as maintain efficiency in operations of existing protocols. The protocol was approved by the National Heart, Lung, and Blood Institutional Review Board (recently changed to General Medicine 1 IRB) in August 2017. During the current reporting period 41 subjects were enrolled (27 healthy volunteers and 14 patients). Over the life of the protocol (as of September 2019) a total of 66 subjects have enrolled (32 healthy volunteers and 34 patients). Research subjects have provided blood samples for DNA gene sequencing for Pulmonary Arterial Hypertension (PAH), immunophenotping for relapsing polychondritis, isolation of B cells for flow cytometry, cell free DNA isolation for PAH, inflammatory marker studies, thrombelastography (TEG) and blood markers of coagulation and fibrinolysis, RNA isolation for sequencing, and vitamin C levels. During the 2018-19 reporting period the following abstract was presented at the American College of Cardiology 68thAnnual Scientific Session, 2019: Plasma Cell-free DNA as a Novel Marker of Disease Severity in Pulmonary Arterial Hypertension (J Am Coll Cardiol, 73(9, S1): S1897, 2019) The following abstract will be presented at the American Heart Association Scientific Sessions, November 2019: Lu M, Blaine K, Cullinane A, Hall C, Dulau-Florea A, Sun J, Chenwi H, Graninger G, Harper B, Elinoff JM, and Solomon MA. Pulmonary Arterial Hypertension Patients Display Normal Kinetics of Clot Formation.